In this successful SAD study, OMS824 was well tolerated and demonstrated linear pharmacokinetics, a long half-life consistent with once daily dosing and good systemic exposure that, at the highest dose administered, resulted in the expected pharmacological effects in healthy subjects. With these encouraging data, Omeros has advanced OMS824 to the next stage of the Phase 1 clinical trial the evaluation of multiple-dose administration of the compound. Omeros expects complete data to be available in early 2013.

"OMS824 appears to have excellent pharmaceutical properties, and we look forward to completing this Phase 1 clinical trial and starting studies in schizophrenia patients," said Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. "While preparing for the next set of OMS824 studies, our pipeline continues to advance toward additional near-term milestones Phase 3 data for OMS103HP this month, an NDA submission next quarter and, for as many as three additional programs, entry into the clinic in 2013."

About Omeros' PDE10 ProgramPDE10 is an enzyme that is expressed in areas of the brain linked to diseases that affect cognition, including schizophrenia and Huntington's disease. Cognitive dysfunction occurs early in these diseases and is responsible for substantial disability. Omeros' proprietary compound OMS824 inhibits PDE10 and is being developed for the treatment of cognitive disorders, including schizophrenia where OMS824 could also have a beneficial effect on the positive (e.g., hallucinations) and negative (e.g., flat affect) symptoms of the disease.

About Omeros CorporationOmeros is a clinical-stage biopharmaceutical company committed to discovering, developing and commercializing products targeting inflammation, coagulopathies and disorders of the central nervous system. The Company's most clinically advanced product candidates are derived from its proprietary PharmacoSurgery platform designed to improve clinical outcomes of patients undergoing a wide range of surgical and medical procedures. Omeros has four ongoing clinical development programs. Omeros may also have the near-term capability, through its GPCR program, to add a large number of new drug targets and their corresponding compounds to the market. Behind its clinical candidates and GPCR platform, Omeros is building a diverse pipeline of protein and small-molecule preclinical programs targeting inflammation, coagulopathies and central nervous system disorders.

Forward-Looking StatementsThis press release contains forward-looking statements as defined within the Private Securities Litigation Reform Act of 1995, which are subject to the "safe harbor" created by those sections. These statements include, but are not limited to, Omeros' expectations regarding when it will announce the remaining data from its Phase 1 clinical trial evaluating OMS824; that it will announce Phase 3 data from its OMS103HP program this month; that it will submit an NDA next quarter for OMS302; that as many as three additional programs will enter the clinic in 2013; and that Omeros may have capability, through its GPCR program, to add a large number of new drug targets and their corresponding compounds to the market. Forward-looking statements are based on management's beliefs and assumptions and on information available to management only as of the date of this press release. Omeros' actual results could differ materially from those anticipated in these forward-looking statements for many reasons, including, without limitation, the risks, uncertainties and other factors described under the heading "Risk Factors" in the Company's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 9, 2012. Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements, and the Company assumes no obligation to update these forward-looking statements publicly, even if new information becomes available in the future.